Brazil's regional airports will require an investment of 2.4bn reais (US$1.5bn) between 2011 and 2015 to deal with growing passenger demand, according to regional air transport association Abetar.

The figure includes 174 municipal and state-run terminals, as well as airports operated by Infraero such as Vitória and Cuiabá, which are not included in federal investments to prepare for the 2014 World Cup, news service Agência Estado reported.

Speaking at a conference on airport concessions, Abetar representative Anderson Correia said he agreed with the results of a study carried out by government-linked thinktank Ipea that showed several airports will not be ready for the sporting event in 2014.

"It's very unlikely that Infraero will manage to meet the schedule of modernization and increasing the capacity of airports within the planned deadline," the executive said.

The Ipea study showed that nine of the 13 airports scheduled for upgrades prior to the event will not be ready by 2014. Terminals in Manaus, Fortaleza, Brasília, Guarulhos, Salvador, Campinas, Cuiabá, Confins and Porto Alegre are all underprepared, the study said.

The federal government sought to address concerns over the preparedness of the country's airports

"In our point of view, the works are on schedule and should meet the needs of the [World] Cup," civil aviation secretary Wagner Bittencourt told reporters.

The government plans to invest 5.6bn reais to update airports in preparation for the 2014 event.